Methoxyflurane: a review with emphasis on its role in dental practice

Inhaled methoxyflurane - an explorable alternative to nitrous oxide?

Nitrous oxide is a widely used and well-established form of inhalation sedation in dentistry. Its properties have a wide margin of safety and allow for anxious, paediatric and adult patients to receive dental treatment with minimal impact upon discharge. Nitrous oxide has drawbacks, however, including its environmental impact and need for specialist equipment. Methoxyflurane is another drug which could prove to be an alternative to nitrous oxide. Methoxyflurane's use has proved popular within emergency medicine in Australia and New Zealand for its potent analgesic effects and recognition of its anxiolytic effect. As a result, its use in invasive outpatient procedures has now become popular. Unfortunately, there is very limited evidence of its use within dentistry as a form of inhalation sedation and analgesic. A wider evidence base should be established, as methoxyflurane could prove to be an effective and environmentally friendly alternative to nitrous oxide.

The environmental impact of nitrous oxide inhalation sedation appointments and equipment used in dentistry

PURPOSE

This paper reports a life cycle impact assessment (LCIA) to calculate the environmental footprint of a dental appointment using N2O, comparing single-use equipment with reusable equipment. Nitrous oxide (N2O) is used successfully in dentistry to provide sedation and pain relief to anxious patients, most commonly in children. However, N2O is a powerful climate pollutant 298 times more damaging than carbon dioxide over a 100-year estimate.

METHODS

The functional unit chosen for this LCIA was 30 min delivery of N2O to oxygen in a 50:50 ratio at 6 L per minute flow rate as inhalation sedation to one patient. Two types of equipment were compared to deliver the anaesthetic gas: reusable and disposable items.

RESULTS

The use of disposable equipment for N2O sedation produces a significantly larger environmental impact across nearly all of the environmental impact scores, but the overall global warming potential is comparable for both types of equipment due to the vast environmental pollution from N2O itself.

CONCLUSION

N2O sedation is a reliable treatment adjunct but contributes to climate change. Single-use equipment has a further deleterious effect on the environment, though this is small compared to the overall impact of N2O. Dental priorities should be to deliver safe and effective care to patients that protects staff, minimises waste and mitigates impact on the environment alongside promoting research into alternatives.

BET 1: Green or blue for you? Methoxyflurane (Penthrox) or nitrous oxide/oxygen 50% mixture (Entonox) for the management of acute pain in the ED

A short-cut review of the literature was carried out to establish whether inhaled methoxyflurane (Penthrox) is comparable or superior with a standard inhalational analgesia for the management of acute pain. Only two papers were identified as suitable for inclusion using the reported search strategy. The author, date and country of publication, patient group studied, study type, relevant outcomes, results and study weaknesses of the best papers are tabulated. It is concluded that both methods of inhaled analgesia appear to be useful options for acute pain in the ED when compared with placebo. No evidence was found to suggest superiority of methoxypenflurane. International studies directly comparing the use of both drugs for in acute trauma are ongoing and will develop the evidence base.